Add ActiveRecord::Enum support. Closes #1993

lib/rails_admin/config/fields/factories/enum.rb

@@ -1,5 +1,6 @@
 require 'rails_admin/config/fields'
 require 'rails_admin/config/fields/types/enum'
+require 'rails_admin/config/fields/types/active_record_enum'
 
 RailsAdmin::Config::Fields.register_factory do |parent, properties, fields|
   model = parent.abstract_model.model
@@ -11,6 +12,9 @@
          model.method_defined?(method_name))
     fields << RailsAdmin::Config::Fields::Types::Enum.new(parent, properties.name, properties)
     true
+  elsif model.respond_to?(:defined_enums) && model.defined_enums[properties.name.to_s]
+    fields << RailsAdmin::Config::Fields::Types::ActiveRecordEnum.new(parent, properties.name, properties)
+    true
   else
     false
   end

lib/rails_admin/config/fields/types/active_record_enum.rb

@@ -0,0 +1,41 @@
+require 'rails_admin/config/fields/types/enum'
+
+module RailsAdmin
+  module Config
+    module Fields
+      module Types
+        class ActiveRecordEnum < Enum
+          RailsAdmin::Config::Fields::Types.register(self)
+
+          def type
+            :enum
+          end
+
+          register_instance_option :enum do
+            abstract_model.model.defined_enums[name.to_s]
+          end
+
+          register_instance_option :pretty_value do
+            bindings[:object].send(name).presence || ' - '
+          end
+
+          register_instance_option :multiple? do
+            false
+          end
+
+          register_instance_option :queryable do
+            false
+          end
+
+          def parse_input(params)
+            if params[name].present?
+              params[name] = enum.invert[params[name].to_i]
+            elsif params[name]
+              params[name] = nil
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/rails_admin/config/fields/types/all.rb

@@ -1,3 +1,4 @@
+require 'rails_admin/config/fields/types/active_record_enum'
 require 'rails_admin/config/fields/types/belongs_to_association'
 require 'rails_admin/config/fields/types/boolean'
 require 'rails_admin/config/fields/types/bson_object_id'

spec/integration/config/edit/rails_admin_config_edit_spec.rb

@@ -963,7 +963,7 @@ def color_enum
       it 'auto-detects enumeration' do
         is_expected.to have_selector('.enum_type select')
         is_expected.not_to have_selector('.enum_type select[multiple]')
-        is_expected.to have_content('green')
+        expect(all('.enum_type option').map(&:text).select(&:present?)).to eq %w(blue green red)
       end
     end
 
@@ -1129,6 +1129,39 @@ def color_enum
     end
   end
 
+  if defined?(ActiveRecord) && ActiveRecord::VERSION::STRING >= '4.1'
+    describe 'ActiveRecord::Enum support', active_record: true do
+      before do
+        class FieldTestWithEnum < FieldTest
+          self.table_name = 'field_tests'
+          enum integer_field: %w(foo bar)
+        end
+        RailsAdmin.config.included_models = [FieldTestWithEnum]
+        RailsAdmin.config FieldTestWithEnum do
+          edit do
+            field :integer_field
+          end
+        end
+      end
+
+      after do
+        Object.send :remove_const, :FieldTestWithEnum
+      end
+
+      it 'auto-detects enumeration' do
+        visit new_path(model_name: 'field_test_with_enum')
+        is_expected.to have_selector('.enum_type select')
+        is_expected.not_to have_selector('.enum_type select[multiple]')
+        expect(all('.enum_type option').map(&:text).select(&:present?)).to eq %w(foo bar)
+      end
+
+      it 'shows current value as selected' do
+        visit edit_path(model_name: 'field_test_with_enum', id: FieldTestWithEnum.create(integer_field: 'bar'))
+        expect(find('.enum_type select').value).to eq '1'
+      end
+    end
+  end
+
   describe 'ColorPicker Support' do
     it 'shows input with class color' do
       RailsAdmin.config Team do